Installing Wood Siding Over Rigid Insulation

Cladding attachment over thick exterior rigid insulation peter baker p eng.

Installing wood siding over rigid insulation.

When installing wood siding over rigid foam sheathing you must protect the siding from moisture and heat buildup and use proper nailing. Moisture protection and heat buildup. To siding 1 embedment 3 5 0 5 1 5 1 5. What are the risks of installing cedar siding directly over foil faced rigid foam insulation should tar paper or housewrap be used as well.

In fact the two products combined make your home super insulated from outside wind and weather. How should wood siding be installed over rigid foam insulation. Cover the house walls with 4 by 8 foot sheets of rigid foam insulation typically 1 2 to 1 inch thick nailed to wood sheathing with 1 1 2 inch broad headed galvanized nails every 16 to 18 inches. Nailing wood siding directly to foam doesn t work because nails have to be extra long to reach through the siding and foam to a solid nail base.

And other non nailable substrates e g. Gypsum sheathing with combined thickness of 1 inch or less method 2 james hardie siding installed to furring strips that are attached through the c i. I don t think builders should install wood siding directly over plastic foam insulation. One of the biggest questions homeowners have about house wrap is whether it can be installed together with foam insulation.

Installation details are key. With foam sheathing an air space is essential both to reduce the siding s water uptake and to provide a. Wood siding applied directly to foam has a history of failures. It adds up to a robust system.

Exterior rigid insulation 1x3 wood furring strips masonry structure 2x4 framing attached to surface of masonry. The answer happily is yes. A vented drainable air space keeps wood siding dry and stable. Method 1 james hardie siding installed directly over continuous insulation c i and other non nailable substrates e g.

Wood siding including cedar siding should be installed over an air space regardless of the type of sheathing used. Since foil faced foam is a moisture barrier it should be used with a continuous film vapor retarder on the inside wall. The illustration below comes from the vinyl siding institute. Plus rigid foam insulation applied over the outside walls.

A homeowner in southwest virginia wants to install engineered wood siding over exterior foam insulation but finds that the manufacturer s installation instructions raises concerns he hadn t thought of.